Why It Matters That Microsoft Will Shut Down This Service for 12 Hours by Barb Darrow @FortuneMagazine July 6, 2016, 1:17 PM EDT E-mail Tweet Facebook Linkedin Share icons One of the supposed benefits of public cloud computing is that if your software is designed right, you should be pretty much insulated from hardware problems and other associated snafus. If your software is parceled out among the tens of thousands of servers running on Amazon amzn , Microsoft, or Google goog cloud data centers worldwide, you should experience minimal downtime. And yet there is still downtime. Fortune recently reported on Oracle policies that allow for a possible 10-hour monthly window for maintenance on some cloud services. Now, Microsoft msft is telling early users of Azure Data Lake that it will be offline for maintenance for 12 hours this weekend starting at 4 p.m. EDT on Saturday, July 9. Get Data Sheet, Fortune’s technology newsletter. For non-techies, Azure Data Lake consists of a big pool of Microsoft-owned-and-operated storage and servers that companies can use to stockpile all sorts of data. This consists of neat row-and-column structured data that sits in tables or databases or the messy, unstructured data that lies in corporate documents. Users can then slice, dice, and purée that data for analysis as needed. An excerpt from an email sent this week to users: Azure Data Lake Store (ADLS) and Azure Data Lake Analytics (ADLA) will be undergoing a scheduled maintenance for 12 hours. During this maintenance window you will not be able to access or use the service… A Microsoft spokeswoman noted that Azure Data Lake is still in preview, meaning it’s not for sale. A Microsoft employee then took to Twitter twtr to point out that a preview product does not have the type of Service Level Agreements, or SLAs, that apply to commercial products. An SLA, a key component of the technology buying process for big companies, usually lays out how product performance will be measured and what remedies the vendor will apply if things go sideways. So, basically, customers shouldn’t care that Azure Data Lake is out because it’s not a real service yet. For more, read: The Battle for Cloud Supremacy The potential problem with that is that while Azure Data Lake may be in “preview,” its website seems to indicate otherwise, noting that Azure Data Lake is “managed and supported with an enterprise-grade SLA.” Not a ton of ambiguity there. If Microsoft wants to split hairs about preview or non-preview, it should get its site in order. This may be a minor kerfuffle in the grand scheme of things. It doesn’t appear that a ton of people use Azure Data Lake, and the maintenance will take place over a summer weekend. But this incident does demonstrate that for all the rosy talk around cloud computing being a totally new IT delivery model, vendors still muddy the waters about what is an actual product and what’s a product-in-the-making. This is not so different from the “vaporware” practice of 20 years ago when software companies like Microsoft msft , IBM ibm , and Borland routinely pre-announced software products and talked about them like they existed months or even years before they hit the market. For more on Microsoft, watch the video: None of that is particularly helpful to customers or would-be customers weighing a move to the cloud.